Cam-actuated positive displacement pumps



June 14, 1966 D. G. WAY 3,

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CAM-ACTUATED POSITIVE DISPLACEMENT PUMPS June 14, 1966 9 Sheets-Sheet 2 Filed Nov. 22, 1963 June 14, 1966 D. G. WAY 3,255,703

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June 14, 1966 D. G. WAY

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CAM-ACTUATED POSITIVE DISPLACEMENT PUMPS' Filed Nov. a2, 1963 9 Sheets-Sheet 5 a. by,

June 14, 1966 D. G. WAY

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CAM-ACTUATED POSITIVE DISPLACEMENT PUMPS Filed Nov. Z2, 1965 9 Sheets-Sheet 8 D. G. WAY

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iomaey United States Patent CAM-ACTUATED The present application is a continuationdn-part of my co-pending application Serial No. 50,631, filed August 19, 1960, now Patent No. 3,112,062.

The present invention relates to cam-actuated positive displacement pumps, both of fixed and variable displacement types and characterized by thier being valveless. The variable displacement pumps are variable, if desired, from a zero pumping capacity to full flow in either direction.

The objectives of the invention may be most readily understood from a consideration of its characteristic features. In accordance with the invention, a rotary pump has a housing for a rotor member comprising a plurality of rotor sections, each including a circular wall and an arcuate part and a Working space. The arcuate parts of the rotor sections project axially from their walls whereby those sections may be fitted together with their arcuate parts disposed towards each other with the arcuate part of one within the working space of the other, the arcuate, interfitted parts being of the same axial length. Working clearances are provided between the sections and between the sections and the housing. The arcuate length of each working space is enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by the adjacent ends of such interfitted arcuate parts. A rotatable drive member extends axially of the rotor by which the rotor member is driven by means operable to turn the sections continuously in one direction but with the interfitted arcuate parts moving at varying relative speeds to cause move ments of their adjacent ends alternately towards and away from each other thus to contract and expand the chambers they define in pumping relationship to intake and discharge ports. The driving means includes parts, one for each rotor section and pivotably connected thereto and connected to the drive member to pivot as the drive member turns. Cam means carried by the housing control the pivoting of the parts to effect the desired expansion of the chambers.

In practice, the cam means includes a cam followe on each part entrant of a cam track which is circular thereby enabling it to be easily and accurately formed and desirably each pump has a cam track at each end of its working space. tracks are eccentrically positioned with respect to the drive member and a further objective of the invention is to provide means enabling the cam tracks to be shifted to vary their eccentric relationship to the drive member thus to vary the volumetric displacement of the pump of which they are a part, desirably, from a zero fiow to a full flow in either direction.

Further objectives of the invention are concerned with various driving means between the drive members and the rotor sections and with various rotor member constructions including side-by-side chamber arrangements.

In the accompanying drawings, illustrative embodiments of the invention are shown from which these and other of its objectives, novel features, and advantages will be readily apparent.

In the drawings:

FIGURE 1 is an elevation of the inner surface of one end wall ofthe housing of a fixed displacement pump in accordance with the invention,

To produce a pumping eitect, the cam "ice FIGURE 2 is an end view of the pump with the end wall shown in FIGURE I removed,

FIGURE 3 is a longitudinal, vertical section of the FIGURE 4 is a longitudinal, vertical section of a variable displacement pump in accordancewith the invention taken approximately along the indicated lines 4-4 of FIGURE 5,

FIGURE 5 is a section taken approximately along the indicated lines 5-5 of FIGURE 4,

FIGURE 6 is a vertical cross sectiontaken centrally of the pump,

FIGURE 7 is a longitudinal, vertical section of a variable displacement pump in accordance with the invention, having chambers arranged side-by-side, the section being taken approximately along the indicated lines 7-7 of FIGURE 8,

FIGURE 8 'is a section taken approximately along the indicated lines 8-8 of FIGURE 7,

FIGURE 9 is a section taken approximately along the indicated lines 9-9 of FIGURE 7,

FIGURE '10 is a section taken approximately along the indicated lines 10-10 of FIGURE 8,

FIGURE 11 is a longitudinal, vertical section of another embodiment of the invention taken approximately along the indicated lines 11-11 of FIGURE 14,

FIGURE 12 is a section taken approximately along the indicated lines 12-12 of FIGURE 14,

FIGURE 13 is a side elevation of the unit,

FIGURE 14 is a section taken approximately along the indicated lines 14-14 of FIGURE 12,

FIGURE 15 is a section taken approximately along the indicated lines 15-15 of FIGURE 11,

FIGURE 16 is a section taken approximately along the indicated lines 16-16 of FIGURE 14,

FIGURE 17 is a longitudinal, vertical section of yet another embodiment of the invention, taken approximately along the indicated lines 117-117 of FIGURE 18,

FIGURE 18 is a section taken approximately along the indicated lines 18-18 of FIGURE 17, and

FIGURE 19 is a section taken approximately along the indicated lines 19-19 of FIGURE 18.

The pump illustrated by FIGURES 1-3 is of the fixed displacement type and has a generally indicated housing 20 having a central section 21 defining a cylindrical working space 22 closed by end plates 23 and 24 bolted thereto which rotatably support a shaft 25 extending axially of the generally indicated working space 22.

Within the working space 22, there is a rotor member consisting of generally indicated rotor sections 26 and 27 which are shown as identical. Each rotor section includes a circular end wall 28, a hub part 29 and an arcuate part 30 extending axially beyond the end of its hub part. The two sections have their arcuate and hub parts disposed towards each other and their arcuate parts are of such arcuate length that the two sections may be fitted together to provide generally indicated chambers 31, each defined by the adjacent ends of the interfitted arcuate parts 30 with the sections being independently rotatable and with working clearances being provided between the sections and between the sections and the housings.

The shaft 25 is so connected to the rotor sections 26 and 27 as to turn them continuously in one direction but at varying relative speeds thus to cause movement of the adjacent ends of the interfitted arcuate portions 30 alternately towards and away from each other to expand and contract the chambers 31 in desired relation to the intake and discharge ports 32 and 33, respectively.

The connections between the shaft 25 and the rotor sections 26 and 27 include cam tracks 34 and 35, respectively, the cam track 34 in the end plate 23 and the cam track 35 being in the end plate 24. The cam tracks are identical and are shown as eccentrically placed true circles, each disposed oppositely to the other. Gear segments 36 and 37 are pivotably supported by respective ones of the end walls 28 of the rotor member sections. The gear segments 36 and 37 include, respectively, cam followers 38 and 39, each for an appropriate one of the cam tracks and confined therein. The gear segments 36 and 37 mesh with gears 40 and 41 fast on the shaft 25. The end walls 28 of therotor sections have Weights 42 counterbalancing the gear segments and cam followers.

The rotary pump illustrated by FIGURES 4-6 is generally similar to the pump just described but includes means by which its volumetric displacement may be varied. A pump in accordance with this embodiment of the invention has a generally indicated housing 43 whose central section 44 defines a cylindrical working space, generally indicated at 45, and has end walls 46 and 47 bolted thereto and rotatably supporting a drive shaft 48 axially of the working space 45.

The rotor member comprises substantially identical, generally indicated rotor sections 49 and 50. Each rotor section consists of a circular end wall 51, a hub part 52, and an arcuate part 53 extending axially beyond the end of the hub part of that section. The two sections have their arcuate and hub parts disposed towards each other and their arcuate parts 53 are of such arcuate length that the two sections may be fitted together to provide generally indicated chamber-s 54, each defined by the adjacent ends of the interfitted arcuate parts 53.

As in the case of the pump illustrated by FIGURES 1, 2, and 3, the rotor sections 49 and are independently rotatable and working clearances are provided between them and between them and their housing. The shaft 48 has gears 55, one for each rotor section. One gear 55 meshes with a gear segment 56 pivotably connected to the end wall of the rotor section 49 and having a cam follower 57, and the other gear 55 meshes with a gear segment 58 pivotably connected to the end wall of the rotor section 50 and having a cam follower 59. Eaeh end wall has a weight 60 counterbalancing its gear segment and cam follower.

In order that rotation of the shaft 48 continuously in the same direction will result in driving the rotor sections 49 and 50 in one direction but at varying speeds thereby to cause movement of the adjacent ends of the interfitted arcuate portions alternately towards and away from each other to expand and contract the chambers 54 in pumping relationship to the intake and discharge ports 61 and 62, cam tracks 63 are provided which receive the cam followers.

Each cam track 63 is shown as a true circle formed in a slide 64. Each slide 64 is slidable in a Way defined by a housing end wall and a transverse shoulder 65 in the housing section 44 and has a transverse slot 66 freely receiving the shaft 48. Each slide is shown as having rack teeth 67 exposed in a chamber 68 in which there is a pinion 69, the pinions 69 being mounted on a shaft 70.

With this construction, the cam tracks may be shifted for example, from one extreme position, see FIGURE 4, into another extreme position in which maximum relative movement between the rotor sections results thereby providing a wide range of control of the volumetric displacement of the pump in either direction with zero pumping effect when the cam tracks are concentric with the shaft 48.

In the embodiment of the invention illustrated by FIGURES 7-10, the pump housing is generally indicated at 71 and has a central section 72 providing a generally indicated working space 73. The section 72 is closed by end walls 74 and 75 rotatably supporting the shaft 76.

The rotor member includes a generally indicated rotor section 77 having a central circular wall 78, a pair 4 of oppositely disposed hub parts 79 and a pair of oppositely disposed arcuate parts 80. The rotor member also includes a pair of substantially identical, generally indicated rotor sections 81 each including a circular wall 82, a hub part 83, and an arcuate part 84.

The shaft 76 is shown supporting a sleeve 85 for rotation independently thereof. The rotor sections 81 are securely fixed on the sleeve 85 as by dutchmans set screws 85A. The rotor section 77 is rotatable independently of the sleeve 85. The arcuate parts 84 of the rotor sections 81 and the arcuate parts 80 of the rotor section 77 are of such arcuate length that the sections may be fitted together to provide generally indicated chambers 86 each defined by the adjacent ends of the interfitted arcuate parts. There are two sets of such chambers, one set on each side of the wall 78. Working clearances are, of course, provided between the sections and between the sections and the housing.

The shaft 76 is provided with gears 86A, both meshing with gear segments 87 and 88. The gear segments 87 and 88 include cam followers 89 and 90, respectively.

The gear segments 87 are pivotably connected to the ends of the rotor section 77 and extend through arcuate slots 91 in the end walls 82 of the sections 81. The gear segments 88 are each attached to an appropriate one of the sections 81. By this arrangement, a pump is provided in which the chambers of both sets are alternately expanded and contracted to effect fluid transfer between the intakes 92 and the discharges 93. The two sets of chambers 86 may act in parallel and they obviously may be placed in series by interconnecting the discharge of one to the intake of the other.

As in the case of the pump illustrated by FIGURES 4-6, the cam followers 89 and are entrant of circular cam tracks 94 each in a slide 95. Each slide 95 is slidable in a way defined by a housing end wall and a shoulder 96 and has a slot 97 receiving the shaft 76. Each slide has rack teeth 98 exposed in a chamber 99 in which there is a pinion 100 meshing with the teeth 98, the pinion 100 being mounted on a common shaft 101.

' The pump illustrated by FIGURES 11-16 has a housing generally indicated at 102 formed by closing the ends of a section 103 with end walls 104 and 105 which rotatably support a shaft 106 extending axially of a generally indicated cylindrical working space 107 for the rotor member. The rotor member has a generally indicated rotor section 108 having a central circular wall 109, a pair of oppositely disposed hub parts 110 and a pair of oppositely disposed arcuate parts 111. The rotor member also includes a pair of substantially identical, generally indicated rotor sections 112 each including a circular end wall 113, a hub part 114, and an arcuate part 115.

The shaft 106 supports an independently rotatable sleeve 116 to which the rotor sections 112 are securely fixed as by dutchmans set screws 116A. The rotor section 108 is rotatable independently of the sleeve 116. Working clearances are provided between the rotor sections and the rotor sections and the housing. The arcuate parts 111 and are of such arcuate length that the rotor sections may be fitted together to provide chambers 117 each defined by the adjacent ends of the interfitted arcuate parts. There are two sets of chambers 117, one set on each side of the central wall 109.

In order that the chambers 117 may be expanded and contracted in pumping relationship to the intakes 118 and the discharges 119, a driving connection between the shaft 106 and the rotor sections 108 and 112 is shown as including a pair of levers 120 pinned to the shaft 106. Links 121 are connected to one end of each of the levers 120 by pivots 122 and to arms 123 by pivots 124 which serve to support cam followers 125. The other extremity of each of the arms 123 is connected to an end wall 113 of rotor sections 112 as by a pivot 126. Links 127 are connected to the other end of each lever by pivots 128 and to arms 129 by pivots 130 provided with cam followers 131. The other end of each arm 129 is connected to the rotor section 108 as by a pivot 132 extending through arcuate slots 133, one in each end wall113.

The cam followers 125 and 131 at each end of the housing 102 are entrant of a circular cam track 134 each in a slide 135 slidably guided between a housing end wall and a transverse shoulder 136. Each slide 135 has a transverse slot 137 for the shaft 106 and also is provided with a threaded bore 138 for the screw 139 rotatably supported by a plate 140 bolted to the housing end walls. Each screw 139 has a gear 141 meshing wit-h a gear 142 on a shaft 143 supported by the housing and provided with a hand wheel 144 enabling the eccentricity of the cam tracks 134 to be varied to establish the desired volumertic displacement of the pump.

The pump shown in FIGURES 17-19 has a housing generally indicated at 145 the central section 146 of which is closed by end walls 147 and 148. The section 146 defines a generally indicated, cylindrical, working space 149 axially of which is a shaft 150 rotatably supported by the end walls 147 and 148. The rotor member has a rotor section generally indicated at 151 which includes a central circular wall 152, a pair of oppositely disposed hub parts 153 and a pair of oppositely disposed arcuate parts 154. The rotor member also includes a pair of substantially identical, generally indicated rotor sections 155 each including a circular end wall 156, a hub part 157, and an arcuate part 158;

The shaft 150 supports a sleeve 159 rotatable independently thereof. The rotor sections 155 are securely anchored to the sleeve 159 as by dutchmans set screws 159A while the rotor section 151.is rotatable independently of the sleeve 159. are provided between the rotor sections and between the rotor sections and the housing. The arcute parts 154 and 158 are of such arcuate length that the rotor sections may be fitted together to provide axially spaced pairs of chambers 160 each defined by the adjacent ends of the interfitted arcuate parts. There are two sets of chambers 160, each set separated from the others by the central wall 152.

In order that the chambers 160 may be expanded and contracted in pumping relations-hip to the intakes 161 and discharge ports 162, a pair of discs 163 are pinned to the shaft 150, one at each end of the rotor member. Links 164, one for each rotor section 155 and pivotably connected as at 165, are connected to a cross head pivot 166 extending through and slidable along a radial slot 167 in the disc 163 with a cam follower 168 attached to its outer end. A link 169 is pivotably connected as at 170 to each end of the rotor section 151 with each pivot 170 extending through an arcuate slot 171 in the adjacent end wall 156. The other end of each link 169 is connected to a cross head pivot 172 slidable in a radial slot 173 in the appropriate disc 163 and with a cam follower 174 attached to its outer end.

The cam followers 168 and 174 are entered in circular cam tracks 175, each in a slide 176 confined between transverse shoulders 177 and the adjacent end walls of the housing 145.

Each slide 176 has a threaded bore 178 receiving a screw 179, each screw 179 being rotatably supported by the housing plate 180 and provided with a gear 181 meshing with a gear 182 on the shaft 183 rotatably supported by the housing.

From the foregoing, it will be apparent that the invention provides positive displacement, rotary pumps combining simplicity of construction with high pumping efficiency and also with means for controlling their displacement from full flow in one direction, for example, through zero discharge to full flow in the opposite direction.

Suitable working clearances- I claim:

1. In a rotary pump, a housing, rotor sections including a circular wall, an arcuate part and a working space, said arcuate parts of the sections projecting axially from their walls whereby the sections may be fitted together with their arcuate parts disposed towards each other and with the arcuate part of one within the working space of the other, the arcuate interfitted parts being of the same axial length, said sections being rotatable independently of each other, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but at varying relative speeds with their adjacent ends moving alternately towards and away from each other thereby to expand and contract said chambers, said means including a plurality of driving parts, one for each rotor section and pivotably connected thereto and connected to said axial member to pivot as said axial member turns, and cam means carried by said housing in control of said driving parts to control the pivoting thereof to effect the desired expansion and contraction of said chamber.

2. In a rotary pump, a housing, rotor sections, each including a circular wall and an arcuate part and a working space, said arcuate parts of the sections projecting axially from their walls whereby the sections may be fitted together with their arcuate parts disposed towards each other and with the arcuate part of one within the working space of the other, the arcuate interfitted parts being of the same axial length, said sections being rotatable independently of each other, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by adjacent ends of said interfitted 'arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but at varying relative speeds with their adjacent ends moving alternately towards and away from each other thereby to expand and contract said chambers, said means including a plurality of driving parts, one for each rotor section and pivotably connected thereto and connected to said axial member to pivot as said axial member turns, and adjustable cam means carried by said housing in control of said driving parts to control the pivoting thereof to effect the desired expansion and contraction of said chamber.

3. The pump of claim 2 in which the cam means is adjustable between a zero and a predetermined maximum pumping effect.

4. The pump of claim 2 in 'which the cam means is adjustable between a zero pump effect and two predetermined maximum pumping effects, one with the flow in one direction and the other with the flow in the other direction.

5. In a rotary pump, a housing, rotor sections each including a circular wall, an arcuate part and a working space, said arcuate parts of the sections projecting axially from their walls whereby the sections may be fitted together with their arcuate parts disposed towards each other and with the arcuate part of one within the working space of the other, the arcuate interfitted parts being of the same axial length, said sections being rotatable independently of each other, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but at varying relative speeds with their adjacent ends moving alternately towards and away from each other thereby to expand and contract said chambers, said means including a plurality of driving parts, one for each rotor section and pivotably connected thereto and connected to said axial member to pivot as said axial member turns, one driving part adjacent each end of said housing, a circular cam track for each driving part carried by said housing eccentrically with respect to said axial member, each driving part including a cam follower entrant of the proximate cam track.

6. In a rotary pump, a housing, rotor sections each including a circular Wall, an arcuate part and a working space, said arcuate parts of the sections projecting axially from their walls whereby the sections may be fitted together with their arcuate parts disposed towards each other and with the arcuate part of one within the working space of the other, the arcuate interfitted parts being of the same axial length, said sections being rotatable independently of each other, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but at varying relative speeds with their adjacent ends moving alternately towards and away from each other thereby to expand and contract said chambers, said means including a plurality of driving parts, one for each rotor section and pivotably connected thereto and connected to said axial member to pivot as said axial member turns, one driving part adjacent each end of said housing, slides having a circular cam track, each driving part including a cam follower entrant of the proximate cam track and adjustable means to actuate said slides to vary the eccentricity of said tracks relative to said axial member.

7. In a rotary pump, a housing, a first rotor section including a central circular wall, a pair of oppositely disposed arcuate parts, and the same number of similarly disposed working spaces, a pair of end rotor sections, each including a circular wall and an arcuate part and a working space, said arcuate parts of the second sections projecting axially from their walls whereby the sections may be fitted together with the arcuate parts of the end sections disposed towards each other and the first section with each arcuate part within the appropriate working space of the first section, the arcuate interfitted parts being of the same axial length, said end sections being interconnected and rotatable independently of the first section, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, two on each side of the central circular wall and each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but with the speed of the first section varying relative to the second sections with the adjacent ends of their arcuate parts moving alternately towards and away from each other thereby to expand and contract said chambers, said connection including a plurality of driving parts, one for each end rotor section and pivotably connected thereto, and at least one for said first section and pivotably connected to an end thereof, all of said driving parts being connected to said axial member to pivot as said axial member turns, and cam means carried by said housing in control of said driving 8 parts to control the pivoting thereof to effect the desired expansion and contraction of said chambers.

8. In a rotary pump, a housing, a first rotor section including a central circular wall, a pair of oppositely disposed arcuate parts, and the same number of similarly disposed working spaces, a pair of end rotor sections, each including a circular wall and an arcuate part and a work-ing space, said arcuate parts of the second sections projecting axially from their walls whereby the sections may be fitted together with the arcuate parts of the end sections disposed towards each other and the first section with each arcuate part within the appropriate working space of the first section, the arcuate interfitted parts being of the same axial length, said end sections being interconnected and rotatable independently of said first section, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, two on each side of the central circular wall and each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but with the speed of the first section varying relative to the second sections with the adjacent ends of their arcuate parts moving alternately towards and away from each other thereby toexpand and contract said chambers, said connection including a plurality of driving parts, one for each end rotor section and pivotably connected thereto and connected to said axial member to pivot as said axial member turns, at least one driving part for said first section and including a pivot connecting it to an end thereof, the proximate end wall of the proximate end section having an arcuate slot through which said pivot extends, a circular cam track carried by said housing adjacent each end thereof eccentrically with respect to said axial member, each driving part including a cam follower entrant of the proximate cam track to control the pivoting thereof to effect the desired expansion and contraction of said chambers.

9. In a rotary pump, a housing, a first rotor section including a central circular wall, a pair of oppositely disposed arcuate parts, and the same number of similarly disposed working spaces, a pair of end rotor sections, each including a circular wall and an arcuate part and a'working space, said arcuate parts of the second sections projecting axially from their walls whereby the sections may be fitted together with the arcuate parts of the end sections disposed towards each other and the first section with each arcuate part within the appropriate working space of the first section, the arcuate interfitted parts being of the same axial length, said end sections being interconnected and rotatable independently of said first section, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, two on each side of the central circular wall and each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but with the speed of the first section varying relative to the second sections with the adjacent ends of their arcuate parts moving alternately towards and away from each other thereby to expand and contra-ct said chambers, said connection including a plurality of driving parts, one for each end rotor section and pivotably connected thereto, and connected to said axial member to pivot as said axial member turns, at least one driving part for said first section and including a pivot connecting it to an end thereof, the proximate end wall of the proximate end section having an arcuate slot through which said pivot extends, slides, one adjacent each end of said housing and having a circular cam track, each driving part including a cam follower entrant of the proximate cam track, and means to actuate said slides to vary the eccentricity of said tracks relative to said axial member.

10. In a rotary pump, a housing, rotor sections, each including a circular wall and an arcuate part and a working space, said arcuate parts of the sections projecting axially from their walls whereby the sections may be fitted together with their arcuate part-s fitted one within the working space of the other, the arcuate interfitted parts being of the same axial length, said sections being rotatable independently of each other, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, a pair of gears fast on said member, one adjacent each end of said housing, and a plurality of gear segments, one for each rotor section and pivotably connected thereto and meshing with an appropriate one of said gears, a cam track adjacent each end of said housing, and each gear segment including a cam follower entrant of an appropriate one of said cam tracks.

11. In a rotary pump, a housing, a first rotor section including a central circular wall, a pair of oppositely disposed arcuate parts, and the same number of similarly'disposed working spaces, a pair of end rotor sections, each including a circular wall and an arcuate part and a working space, said arcuate parts of the second sections projecting axially from their walls whereby the sections may be fitted together with the arcuate parts of the end sections disposed towards each other and the first section with each arcuate part within the approximate working space of the first section, the arcuate interfitted parts being of the same axial length, said end sections being interconnected and rotatable independently of said first section, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, two on each side of the central circular wall and each defined by adjacent ends of said interfitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but with varying speeds of the first section relative to the second sections with the adjacent ends of their arcuate parts moving alternately towards and away from each other thereby to expand and contract said chambers, said connection including a plurality of driving parts, one for each end rotor section and pivotably connected thereto, and at least one for said first section and pivotably connected to an end thereof, each of said driving parts including a cam follower, driving members fast on said axial member, one adjacent each end of said housing, a link pivotably connecting each driving part to an appropriate one of said driving members, and cam tracks, one at each end of said housing and receiving and guiding the cam followers of proximate driving parts.

12. In a rotary pump, a housing, a first rotor section including a central circular wall, a pair of oppositely disposed arcuate parts, and the same number of similarly disposed working spaces, a pair of end rotor sections, each including a circular wall and an arcuate part and a working space, said arcuate parts of the second sections projecting axially from their walls whereby the sections may be fitted together with the arcuate parts of the end sections disposed towards each other and the first section with each arcuate part within the approximate working space of the first section, the arcuate interfitted parts being of the same axial length, said end sections being interconnected and rotatable independently of said first section, there being working clearances between the sections and between the sections and the housing, the arcuate length of each working space being enough greater than that of the arcuate part fitted therein to permit one section to turn relatively to the other and to provide chambers, two on each side of the central circular wall and each defined by adjacent ends of said inter fitted arcuate parts, a rotatable axial member, and a connection between said member and said sections operable to turn said sections continuously in one direction but with varying speeds of the first section relative to the second sections with the adjacent ends of their arcuate parts moving alternately towards and away from each other thereby to expand and contract said chambers, said connection including a plurality of driving parts, one for each end rotor section and pivotably connected thereto, and at least one for said first section and pivotably connected to an end thereof, driving members fast on said axial member, one adjacent each end of said housing, pivot means connecting each driving part to an appropriate driving member and slidable radially thereof, and cam tracks, one at each end of said housing, each pivot means including a cam follower entrant of the proximate cam trac References Cited by the Examiner UNITED STATES PATENTS 1,007,866 11/1911 Greene 230-144 1,502,756 7/1924 Thompson 103129 1,843,155 2/1932 Gronemeyer 103129 2,085,505 6/1937 Murakami 123-11 2,096,074 10/ 1937 Stevens 103-129 2,149,143 2/1939 Landenberger 103-129 2,426,361 8/1947 Lester 103129 2,544,480 3/1951 Bancroft 123-11 2,544,481 3/1951 Bancroft 103129 3,112,062 11/1963 Way 230139 FOREIGN PATENTS 944,904 11/ 1948 France.

MARK NEWMAN, Primary Examiner. 

1. IN A ROTARY PUMP, A HOUSING, ROTOR SECTIONS INCLUDING A CIRCULAR WALL, AN ARCUATE PART AND A WORKING SPACE, SAID ARCUATE PARTS OF THE SECTIONS PROJECTING AXIALLY FROM THEIR WALLS WHEREBY THE SECTIONS MAY BE FITTED TOGETHER WITH THEIR ARCUATE PART DISPOSED TOWARDS EACH OTHER AND WITH THE ARCUATE PART OF ONE WITHIN THE WORKING SPACE OF THE OTHER, THE ARCUATE INTERFITTED PARTS BEING OF THE SAME AXIAL LENGTH, SAID SECTIONS BEING ROTATABLE INDEPENDENTLY OF EACH OTHER, THERE BEING WORKING CLEARANCES BETWEEN THE SECTIONS AND BETWEEN THE SECTIONS AND THE HOUSING, THE ARCUATE LENGTH OF EACH WORKING SPACE BEING ENOUGH GREATER THAN THAT OF THE ARCUATE PART FITTED THEREIN TO PERMIT ONE SECTION TO TURN RELATIVELY TO THE OTHER AND TO PROVIDE CHAMBERS, EACH DEFINED BY ADJACENT ENDS OF SAID INTERFITTED ARCUATE PARTS, A ROTATABLE AXIAL MEMBER, AND A CONNECTION BETWEEN SAID MEMBER AND SAID SECTIONS OPERABLE TO TURN SAID SECTIONS CONTINUOUSLY IN ONE DIRECTION BUT VARYING RELATIVE SPEEDS WITH THEIR ADJACENT ENDS MOVING ALTERNATELY TOWARDS AND AWAY FROM EACH OTHER THEREBY TO EXPAND AND CONTRACT SAID CHAMBERS, SAID MEANS INCLUDING A PLURALITY OF DRIVING PARTS, ONE FOR EACH ROTOR SECTION AND PIVOTABLY CONNECTED THERETO AND CONNECTED TO SAID AXIAL MEMBER TO PIVOT AS SAID AXIAL MEMBER TURNS, AND CAM MEANS CARRIED BY SAID HOUSING IN CONTROL OF SAID DRIVING PARTS TO CONTROL THE PIVOTING THEREOF TO EFFECT THE DESIRED EXPANSION AND CONTRACTION OF SAID CHAMBER. 